For example, an apparatus having an arrangement shown in FIGS. 22 and 23 has been generally known as a high-speed large-capacity disk storage apparatus such as a removable hard disk apparatus which is typical thereof, or the like.
This removable disk storage apparatus 1 employs a rotation actuator and has a apparatus body 2, a disk cartridge 3 detachably loaded onto this apparatus body 2, and so on. The apparatus body 2 has a chassis 4 having a cartridge accommodation chamber for accommodating the disk cartridge 3, a rotation actuator rotatably supported by the chassis 4, a magnetic head 6 attached to a tip end of the rotation actuator 5, a spindle motor 7 supported by the chassis 4 so as to be capable of being moved upward and downward, and so on.
A chucking magnet is attached to a rotation shaft of the spindle motor 7. A lifting mechanism, not shown, is operated in an interlocking operation with an operation of inserting and ejecting the disk cartridge 3, thereby the spindle motor 7 and the chucking magnet 8 being lifted up and down. As a result, when the spindle motor 7 is lifted up, the chucking magnet 8 chucks a metal hub 13 attached to a magnetic disk 9 accommodated in the disk cartridge 3, thereby the magnetic disk 9 being rotated together with the spindle motor.
The disk cartridge 3, as shown in FIG. 24 which is an exploded diagram showing a general arrangement thereof, has a pair of upper and lower shells 10, 11, the magnetic disk 9 rotatably accommodated in a disk accommodation chamber 12 between both of the shells 10, 11, and so on. The magnetic disk 9 has the metal hub 13 attached thereto such that its lower portion is rotatably engaged with a hub aperture 14 of the lower shell 11. Moreover, the disk cartridge 3 has a head insertion slot 15 permitting the rotation actuator 5 to be inserted thereinto and drawn therefrom. A shutter 16 for opening and closing the head insertion slot 15 is attached to the head insertion slot, and the shutter 16 prevents dusts from being entering the disk cartridge when the disk cartridge is not loaded.
The shutter 16 of the disk cartridge 3 is rotatably supported by the upper shell 10 at projections 16a projected from their both ends. The shutter 16 is rotated by a shutter opening and closing mechanism, not shown, attached to the apparatus body 2 and a free end side of the shutter 16 is rotated so as to be projected outward from the head insertion slot 15, thereby the head insertion slot 15 being opened. Thus, the rotation actuator 5 can be inserted into the head insertion slot.
Thus, as shown in FIG. 22, when the disk cartridge 3 is inserted into the removable disk storage apparatus 1, the shutter 16 of the disk cartridge 3 is automatically opened by the shutter opening and closing mechanism. When the disk cartridge 3 is inserted and reaches a predetermined position, the spindle motor 7 is lifted up to attract the metal hub 13 by a magnetic force of the chucking magnet 8. Thus, the magnetic disk 9 and spindle motor 7 can be rotated together (chucking).
When the spindle motor 7 is rotated and a angular speed of the magnetic disk 9 becomes constant, the magnetic head 6 provided at the tip end of the rotation actuator 5 is brought close to a recording surface of the magnetic disk 9. Thus, preparation for recording (reproducing) information on (from) the magnetic disk 9 is completed and then a predetermined signal is supplied to the magnetic head 9, which enables a desired information to be recorded on (or reproduced from) the information recording surface of the magnetic disk 9.
An apparatus having an arrangement shown in FIG. 25 has been known as a conventional removable disk storage apparatus. This removable disk storage apparatus 17 employs a linear-movement actuator and is remarkably different from the above-mentioned removable disk storage apparatus 1 in that a linear-movement actuator 18 is moved straight.
Specifically, the removable disk storage apparatus 17 has an apparatus body 19 having the linear-movement actuator 18 and a disk cartridge 20. The linear-movement actuator 18 is disposed at the center of a bottom portion of a chassis 4 with a magnetic head provided at its tip end being faced toward an insertion slot of the apparatus body 19. The disk cartridge 20 has a head insertion slot 21 provided at the center of a bottom portion of the disk cartridge 20 so as to be opposed to the linear-movement actuator. A slidable shutter similar to a shutter employed by a 3.5-inch floppy disk cartridge is provided at the head insertion slot 21. When the slidable shutter is slid in the width direction of the disk cartridge, the head insertion slot 21 is opened and closed.
However, since the removable disk storage apparatus employing the rotation actuator has the rotation actuator 5 which can be rotated in the horizontal direction and whose tip end portion enters the head insertion slot 15 of the disk cartridge 3 in the direction from the diagonal side as shown in FIG. 22, a horizontal-direction length of the head insertion slot 15 must be sufficiently long so that the magnetic head 6 attached to the tip end of the rotation actuator 5 can be moved toward the innermost side of the information storage surface, i.e., close to the metal hub. As a result, such removable disk storage apparatus cannot employ a slidable shutter which must be inevitably slid by a considerable length, and hence inevitably employ a rotation shutter described above as the shutter 16.
However, when the rotary shutter is employed, even if the rotary shutter is closed, clearances are easily produced around the head insertion slot 15. Therefore, dusts which are great menaces to the storage apparatus of this kind easily enter the disk cartridge. Moreover, since the rotary shutter requires the projections 16a as a rotation center of the shutter 16, not only a shaft diameter of the projection 16a but also the supporting mechanism therefor must have certain thicknesses, which makes it difficult to make the cartridge thinner, and the stress is intensively applied to the projections 16a, which lowers the reliability of strength of the shutter.
When the linear-movement actuator is employed, the linear-movement actuator 18 can be moved straight and hence the tip end portion of the linear-movement actuator 18 enters the head insertion slot 21 of the disk cartridge 3 straight. Therefore, even when the magnetic head 6 provided at the tip end of the linear-movement actuator 18 is moved close to the metal hub 13, the horizontal-direction length of the head insertion slot 21 needs not to be long and hence the removable disk storage apparatus can employ the above slidable shutter.
However, since the linear-movement actuator 18 tends to be easily influenced by an external disturbance upon its linear movement, it is impossible to secure high shock-proof property against a shock applied to the disk storage apparatus. Moveover, since the linear-movement actuator 18 has a large inertial mass as compared with that of the rotary actuator 5, a seek speed of the disk storage apparatus employing the linear-movement actuator 18 becomes slow as compared with one employing the rotary actuator 5. Moreover, since an arrangement of the linear-movement actuator 18 is complicated as compared with that of the rotary actuator 5, manufacturing costs for the linear-movement actuator are increased as compared with those of the rotary actuator.
The present invention is made in view of the above problems, and it is an object of the present invention to provide a disk storage apparatus which employs a rotary actuator mechanically excellent as compared with a linear-movement actuator and can employ, in a disk cartridge, a slidable shutter that easily prevents dusts from entering the disk cartridge, and a disk cartridge therefor.